One software development problem relates to the use of two or more programming languages to implement a software project under development. By way of example, but not limitation, there is currently significant interest in the use of both the Java and C++ programming languages in developing a given software application. In other words, recent advantages in computational languages, particularly object-oriented programming languages, have given rise to the situation where a given software product may, for any of a number of business or computational reasons, require implementation in more than one programming language.
It will be appreciated that the largest problem to be dealt with when mixing languages in a given program is that the several languages are usually very different. If this were not the case, there would be little reason for using more than one language to write the program. Certain combinations of languages have so little in common, that the sharing of data between the languages is nearly impossible, except through file transfer or some other means of external streaming of the data. This gives rise to the problem that the program units written in the several languages require the conversion of the data therebetween in order to communicate it to other units of a different language. Sometimes, it is not known which language another program unit is written in and it therefore becomes necessary to convert the data before passing it to a program unit written in the same language.
The solution to this problem has heretofore been to choose the several programming languages very carefully. It is often the case that a developer will use a special purpose language, such as Java, and a very general-purpose language, like C, and tries to express the former in terms of the latter. While this is occasionally possible, it is extremely difficult to implement, because the general-purpose language expression of the special-purpose language is usually very involved. Accordingly, the cost of programming in this manner is substantially increased.
This problem occurs since programming languages are generally developed without any intent of mixing them with any given single application. Accordingly, the compilers for the several languages are not coordinated with one another. This shifts the problem of presenting a unified representation of the data, best taken care of by the compiler to the programmer. As previously discussed, the cost of programming in an environment where data must be converted to a third representation, e.g. so-called transfer files, or where a developer must use a language which is too general in purpose, is high. This, of course, adversely effects programmer productivity and the attendant production costs of the software program.
Having reference to FIG. 1, and further to the discussion of the C++ and Java programming languages, it should be noted that the concepts capable of facile implementation in Java are generally implementable in C++, although the converse is not necessarily the case. The congruency between the more generalized language, C++ and the more specialized language, Java is shown in the Venn diagram of the figure. This congruence, along with certain marked similarities in the syntax of the two languages, gives rise to the possibility that a methodology might be found which will enable a software developer to mix languages in a program under development. If this language mixing could be effected by sharing data therebetween with minimal developer input and without computational performance penalties, significant advantages in computational efficiency and programmer productivity would accrue.